Nerve modulation therapies such as nerve ablation are beneficial for certain conditions. For example, sympathetic renal activity connected with congestive heart failure may cause unwanted symptoms such as fluid retention. Interrupting this sympathetic nerve activity may mitigate these symptoms. One technique for interrupting the renal sympathetic nerve activity is to ablate the sympathetic nerves, which are disposed in part around the renal arteries. Typical renal nerve ablation therapies involve the introduction of an ablation catheter into the renal arteries and ablating the arteries at various longitudinal and radial locations along the arteries. This procedure is done without identifying the specific location of the nerve tissue or identifying the nerve tissue.